JP2022038103A - Printer and printing method - Google Patents

Abstract

To inhibit deterioration in printing quality in a printer provided with a serial head in which an impact position of a satellite droplet is deviated relative to an impact position of a main droplet.SOLUTION: A printer includes: a head for discharging liquid on a printing medium; a carriage which reciprocally moves the head to one side and the other side in a scanning direction relative to the printing medium; and a control unit for printing a print image using liquid by controlling drive of the head and the carriage. The control unit performs printing according to first scanning of moving the head from one side to the other side, when printing one end of the print image, and performs printing according to second scanning of moving the head from the other side to the one side, when printing the other end of the print image.SELECTED DRAWING: Figure 7

Description

The present invention relates to a printing apparatus and a printing method for discharging and printing a liquid.

The serial head type inkjet printer has a pass operation for ejecting ink droplets while reciprocating the head for ejecting ink droplets in the scanning direction with respect to the print medium, and moving the print medium in a transport direction intersecting the scanning direction. By alternately repeating the transfer operation, dots arranged in the scanning direction are arranged and formed in the transfer direction, and an image is formed on the print medium. At this time, when a phenomenon occurs in which the landing position of the dots ejected corresponding to the predetermined position in the scanning in the outward direction of the head and the landing position of the dots ejected corresponding to the predetermined position in the scanning in the return direction deviate from each other. There is. When code information such as a barcode is printed in a state where there is such a deviation in the landing position of the dots, the dimensions of the elements constituting the code may vary or the shape may be distorted, resulting in deterioration of the quality of the code. .. Poor quality code can cause read errors when reading code information.
On the other hand, in Patent Document 1, it is confirmed whether code information such as a barcode is included in the data to be printed in the next scan, and if the code information is included, one-way printing is performed, and other than that. In this case, an inkjet printing device that suppresses deterioration of code quality due to landing position deviation caused by a difference in scanning direction by performing bidirectional printing is described.

Japanese Unexamined Patent Publication No. 2005-47168

However, in an inkjet printer, the ink droplets ejected by the head may split into a main droplet and one or more satellite droplets following the main droplet at the time of ejection or immediately after ejection. Since the landing of satellite droplets is delayed with respect to the landing of the main droplets, in a serial head type inkjet printer that ejects ink droplets while reciprocating the head in the scanning direction, the landing position in the scanning direction is deviated. This also applies to the printing apparatus described in Patent Document 1, and even when the area including the code information is printed by one-way printing, the landing position of the satellite drop is relative to the landing position of the main drop. There is a problem that, for example, the dimensions of each element constituting the barcode may vary or the shape may be distorted, resulting in deterioration of the code quality.

The printing apparatus of the present invention controls a head that discharges liquid to a printing medium, a carriage that reciprocates the head from one side to the other in the scanning direction with respect to the printing medium, and the driving of the head and the carriage. The control unit includes a control unit for printing a printed image of the liquid, and the control unit moves the head from one of the heads to the other when printing one end of the printed image. When printing is performed and the other end of the printed image is printed, printing is performed by a second scan in which the head is moved from the other to the one.

The printing method of the present invention prints a printed image on a printing apparatus including a head that ejects liquid to a printing medium and a carriage that reciprocates the head from one side to the other in the scanning direction with respect to the printing medium. When printing the one end of the printed image, the printing is performed by the first scan in which the head is moved from the one to the other, and the other end of the printed image is printed. Is printed by a second scan in which the head is moved from the other side to the other side.

It is a front view which shows the structure of the printing apparatus which concerns on embodiment. It is a block diagram which shows the structure of the printing apparatus which concerns on embodiment. It is a schematic diagram which shows the example of the arrangement of the nozzles seen from the lower surface of a head. It is explanatory drawing of the basic function of a printer driver. It is a conceptual diagram explaining the state of flight of the ejected ink droplet. It is a conceptual diagram which shows the example of the printed image in the prior art in the case where there is a deviation in the landing position of a main drop and a satellite drop. It is a conceptual diagram which shows the example of the print image printed by the printing apparatus and the printing method which concerns on embodiment. It is a conceptual diagram which shows another example of the printed image in the prior art in the case where there is a deviation in the landing position of a main drop and a satellite drop. It is a conceptual diagram which shows another example of the print image printed by the printing apparatus and the printing method which concerns on embodiment. It is a conceptual diagram which shows the other example of the printed image in the prior art in the case where there is a deviation in the landing position of a main drop and a satellite drop. It is a conceptual diagram which shows the other example of the print image printed by the printing apparatus and the printing method which concerns on embodiment.

The configuration of the printing apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 2.
In the coordinates added to the drawings, the Z-axis direction is the vertical direction, the + Z direction is the upward direction, the X-axis direction is the front-back direction, the -X direction is the front direction, the Y-axis direction is the left-right direction, and the + Y direction is the left direction. The XY plane is a horizontal plane.

The printing device 1 is composed of a printing unit 100 and an image processing unit 110 connected to the printing unit 100.
Based on the print data received from the image processing unit 110, the printing unit 100 applies ink as a liquid to the long printing medium 5 set in a rolled state to obtain a desired image. It is an inkjet printer that prints.

The image processing unit 110 includes an image control unit 111, an input unit 112, a display unit 113, a storage unit 114, and the like, and controls a print job that causes the print unit 100 to print. Further, the image processing unit 110 generates print data for causing the print unit 100 to print a desired image based on the image data. The image processing unit 110 is configured by using a personal computer as a suitable example.
The software on which the image processing unit 110 operates includes general image processing application software that handles image data to be printed, and printer driver software that controls the printing unit 100 and generates print data for causing the printing unit 100 to execute printing. Includes a color conversion lookup table creation program that creates the color conversion lookup table required to generate print data. In the following description, the image processing application software is simply referred to as an image processing application, and the printer driver software is simply referred to as a printer driver.
Here, the image data is RGB digital image information including code information such as a bar code, line drawing, and text data.

The image control unit 111 includes a CPU 115, an ASIC 116, a DSP 117, a memory 118, an in-device interface 119, a general-purpose interface 120, and the like, and centrally manages the entire printing device 1. CPU means Central Processing Unit, ASIC means Application Specific Integrated Circuit, and DSP means Digital Signal Processor.
The input unit 112 is an information input means as a user interface. Specifically, for example, a keyboard or a mouse pointer.
The display unit 113 is an information display means as a user interface, and under the control of the image control unit 111, information input from the input unit 112, an image to be printed on the print unit 100, information related to a print job, and the like. Is displayed.

The storage unit 114 is a rewritable storage medium such as a hard disk drive or a memory card, and information related to a program operated by the image control unit 111 as software for operating the image processing unit 110, an image to be printed, and a print job. Etc. are memorized.
The memory 118 is a storage medium that secures an area for storing a program in which the CPU 115 operates, a work area in which the CPU 115 operates, and the like, and is composed of storage elements such as RAM and EEPROM. RAM means Random access memory, and EEPROM means Electrically Erasable Programmable Read-Only Memory.
The general-purpose interface 120 is an interface to which an external electronic device can be connected, such as a LAN interface or a USB interface. LAN means Local Area Network, and USB means Universal Serial Bus.
In the present embodiment, the general-purpose interface 120 is a data acquisition unit that acquires image data from an external electronic device under the control of the CPU 115.

The printing unit 100 includes an ink applying unit 10, a moving unit 20, a printing control unit 30, and the like. The printing unit 100, which has received the print data from the image processing unit 110, controls the ink application unit 10 and the moving unit 20 by the print control unit 30 based on the print data, and prints the image on the print medium 5.
The print data is data for image formation obtained by converting image data so that it can be printed by the print unit 100 by an image processing application included in the image processing unit 110 and a printer driver, and includes a command for controlling the print unit 100. There is.

The ink applying unit 10 is composed of a head unit 11, an ink supply unit 12, and the like.
The moving unit 20 is composed of a scanning unit 40, a transport unit 50, and the like.
The scanning unit 40 includes a carriage 41, a guide shaft 42, a carriage motor, and the like. The carriage motor is not shown.
The transport unit 50 includes a supply unit 51, a storage unit 52, a transport roller 53, a platen 55, and the like.

The head unit 11 includes a head 13 and a head control unit 14 having a plurality of nozzles for ejecting printing ink as ink droplets. The head unit 11 is mounted on the carriage 41, that is, the head 13 is mounted on the carriage 41 and reciprocates in the X-axis direction along with the carriage 41 that moves in the X-axis direction as the scanning direction.

As the ink, a four-color ink set obtained by adding black ink to a three-color ink set of cyan, magenta, and yellow is used.
As shown in FIG. 3, the head 13 has four nozzle rows 16 in which a plurality of nozzles 15 for ejecting ink of each color are arranged side by side, specifically, a black ink nozzle row K and a cyan ink nozzle row. It includes four nozzle rows 16 of C, a magenta ink nozzle row M, and a yellow ink nozzle row Y. The nozzle rows 16 are aligned and arranged so as to be parallel to each other at regular intervals in the scanning direction.

The ink supply unit 12 includes an ink tank and an ink supply path for supplying ink from the ink tank to the head 13. The ink tank and the ink supply path are not shown.
The ink tank, the ink supply path, and the ink supply path to the nozzle 15 for ejecting the same ink are provided independently for each ink.
The ink is not limited to the above four colors of ink. For example, an eight-color ink set including ink sets such as light cyan, light magenta, light yellow, and light black, in which the density of each color material is lightened, is used, and a head corresponding to eight colors is provided. May be good.

The moving unit 20, that is, the scanning unit 40 and the transport unit 50, moves the print medium 5 relative to the head 13 under the control of the print control unit 30.
The guide shaft 42 extends in the X-axis direction and supports the carriage 41 in a slidable state. Further, the carriage motor serves as a drive source for reciprocating the carriage 41 along the guide shaft 42. That is, the scanning unit 40 moves the carriage 41, that is, the head 13 along the guide shaft 42 in the X-axis direction under the control of the print control unit 30. The head 13 provided in the head unit 11 mounted on the carriage 41 ejects ink droplets to the print medium 5 supported by the platen 55 under the control of the print control unit 30 while moving in the X-axis direction. A plurality of dot rows along the X-axis direction are formed on the print medium 5.
In the present embodiment, the image control unit 111 and the print control unit 30 configure a control unit 60 that controls the head 13 and the moving unit 20 based on the image data to perform printing.

The supply unit 51 rotatably supports the reel on which the print medium 5 is wound in a roll shape, and sends the print medium 5 to the transport path. The storage unit 52 rotatably supports a reel for winding the print medium 5, and winds the printed medium 5 for which printing has been completed from the transport path.
The transport roller 53 includes a drive roller that moves the print medium 5 and a driven roller that rotates with the movement of the print medium 5, and is a Y-axis as a transport direction that intersects the scanning direction with the print medium 5 on the upper surface of the platen 55. Move in the direction. The transport roller 53 constitutes a transport route for transporting the print medium 5 from the supply unit 51 to the storage unit 52 via the print area of the ink applying unit 10. The print area is an area on the upper surface of the platen 55 where the head 13 moves in the X-axis direction.
The platen 55 is a flat plate extending in the XY plane direction and supporting the print medium 5 in the print area. The platen 55 is provided so that the distance PG from the head 13 can be changed according to the thickness of the print medium 5.

The print control unit 30 includes an in-device interface 31, a CPU 32, a memory 33, a drive control unit 34, and the like, and controls the print unit 100.
The in-device interface 31 is connected to the in-device interface 119 of the image processing unit 110, and data is transmitted / received between the image processing unit 110 and the printing unit 100.
The CPU 32 is an arithmetic processing unit for controlling the entire printing unit 100.
The memory 33 is a storage medium that secures an area for storing a program in which the CPU 32 operates, a work area in which the CPU 32 operates, and the like, and is composed of storage elements such as RAM and EEPROM.
The CPU 32 controls the ink application unit 10 and the moving unit 20 via the drive control unit 34 according to the program stored in the memory 33 and the print data received from the image processing unit 110.

The drive control unit 34 includes firmware that operates based on the control of the CPU 32, and controls the drive of the head unit 11 of the ink application unit 10, the ink supply unit 12, the scanning unit 40 of the moving unit 20, and the transport unit 50. The drive control unit 34 includes a drive control circuit including a movement control signal generation circuit 35, a discharge control signal generation circuit 36, a drive signal generation circuit 37, and the like, and a ROM or flash memory containing firmware for controlling these drive control circuits. Has been done. The ROM and flash memory containing the firmware that controls the drive control circuit are not shown. Here, ROM means Read-Only Memory.

The movement control signal generation circuit 35 is a circuit that generates a signal for controlling the scanning unit 40 and the transport unit 50 of the moving unit 20 according to an instruction from the CPU 32 based on the print data.
The ejection control signal generation circuit 36 generates a head control signal for selecting a nozzle 15 for ejecting ink, selecting an ejection amount, controlling ejection timing, and the like according to an instruction from the CPU 32 based on print data. It is a circuit.
The drive signal generation circuit 37 is a circuit that generates a drive signal for driving the pressure generation chamber included in the head 13.

With the above configuration, the print control unit 30 moves the carriage 41 that supports the head 13 along the guide shaft 42 in the X-axis direction with respect to the print medium 5 supplied to the print area by the supply unit 51 and the transfer roller 53. While repeating the operation of ejecting ink droplets from the head 13 and the operation of moving the print medium 5 in the + Y direction intersecting the X-axis direction by the transport roller 53, a desired image is printed on the print medium 5.

Printing on the print medium 5 is started by transmitting print data from the image processing unit 110 to the print unit 100. The print data is generated by the printer driver.
Hereinafter, the print data generation process performed by the printer driver will be described with reference to FIG.

The printer driver receives image data from an image processing application, converts it into print data in a format that can be interpreted by the print unit 100, and outputs the print data to the print unit 100. When converting image data from an image processing application into print data, the printer driver performs resolution conversion processing, color conversion processing, halftone processing, rasterization processing, command addition processing, and the like.
When the printer driver performs the print data generation process, the step of receiving the image data from the image processing application is the step of acquiring the image data in the present embodiment.

The resolution conversion process is a process of converting the image data output from the image processing application into the resolution for printing on the print medium 5. For example, when the resolution for printing is specified as 720 × 720 dpi, the vector format image data received from the image processing application is converted into the bitmap format image data having a resolution of 720 × 720 dpi. Each pixel data of the image data after the resolution conversion process is composed of pixels arranged in a matrix. Each pixel has a gradation value of, for example, 256 gradations in the RGB color space. That is, the pixel data after the resolution conversion indicates the gradation value of the corresponding pixel. Hereinafter, the gradation value data in the RGB color space is referred to as RGB data.
Pixel data corresponding to one row of pixels arranged in a predetermined direction among the pixels arranged in a matrix is called raster data. The predetermined direction in which the pixels corresponding to the raster data are arranged corresponds to the moving direction of the head 13 when printing an image, specifically, the X-axis direction. The moving direction of the head 13 is a relative moving direction in which the head 13 and the print medium 5 move relatively.

The color conversion process is a process of converting the RGB data of the image data into the gradation value data of the CMYK color space. The CMYK colors are cyan, magenta, yellow, and black, and the image data in the CMYK color space is data corresponding to the color of the ink possessed by the printing unit 100. Therefore, for example, when the printing unit 100 uses four types of inks of the CMYK color system, the printer driver generates image data of the four-dimensional space of the CMYK color system based on the RGB data. The gradation value data in the CMYK color space is, that is, ink amount data. Hereinafter, the gradation value data of the CMYK color space is referred to as CMYK data.
This color conversion process is performed based on a color conversion lookup table in which the gradation value of RGB data and the gradation value of CMYK data are associated with each other. The pixel data after the color conversion process is, for example, 256 gradation CMYK data represented by the CMYK color space. In the present embodiment, the step of performing this color conversion process is an ink amount data generation step of generating ink amount data based on the acquired image data.

The halftone process is a process of converting high gradation data, for example, 256 gradation data, into data having a gradation number that can be formed by the printing unit 100. By this halftone processing, the data indicating 256 gradations can be, for example, 1-bit halftone data indicating 2 gradations with and without dots, or 4 gradations of no dots, small dots, medium dots, and large dots. It is converted into the shown 2-bit halftone data. Specifically, the dot generation rate corresponding to the gradation value is obtained from the dot generation rate table corresponding to the gradation value of 0 to 255 and the dot generation rate. As for the dot generation rate obtained corresponding to the gradation value, for example, in the case of 4 gradations, the generation rates of no dot, small dot, medium dot, and large dot are obtained. At each of the obtained generation rates, pixel data is created so that the dots are dispersed and formed by using a dither method, an error diffusion method, or the like.

The rasterize process is a process of rearranging the above-mentioned 1-bit or 2-bit pixel data arranged in a matrix according to the dot formation order at the time of printing. The raster rise process includes a path allocation process of allocating image data composed of pixel data after halftone processing to each path for ejecting ink droplets while the head 13 moves. When the path allocation is completed, the actual nozzles 15 forming each raster line constituting the printed image are allocated. Here, the print image means an image printed on the print medium 5 or an image of an image printed on the print medium 5.

The command addition process is a process of adding command data according to the printing method to the rasterized data. The command data includes, for example, transfer data related to the transfer specifications of the print medium 5. The transport specifications are, for example, the amount and speed of movement of the print medium 5 on the upper surface of the platen 55 in the transport direction.
The series of processes by the printer driver is performed by the ASIC 116 and the DSP 117 under the control of the CPU 115, and in the print data transmission process, the print data generated by the series of processes is printed by the printing unit 100 via the in-device interface 119. Will be sent to.

Next, with reference to FIG. 5, the state of flight of the ink droplets ejected from the nozzle 15 will be described.
The print medium 5 is placed on the upper surface of the platen 55 extending in the XY plane direction. The opening surface of the nozzle 15 included in the head 13 is located at a distance PG from the upper surface of the platen 55 in the + Z direction. The nozzle 15 ejects ink droplets in the −Z direction while reciprocating in the X-axis direction. FIG. 5 shows how the nozzle 15 is moving in the + X direction at a speed Vc.

As shown in FIG. 5, the ink droplet ejected from the nozzle 15 may be split into a main droplet and one or more satellite droplets after ejection. The flight speeds of the main drop and the satellite drop are different, and when the flight speed of the main drop is Vm and the flight speed of the satellite drop is Vs, Vm> Vs. Further, since the nozzle 15 is moving in the X direction at a velocity Vc, the actual velocity vectors of the main droplet and the satellite droplet are Vm'and Vs'. As a result, the positions where the main droplet and the satellite droplet land on the print medium 5 are Pm and Ps, and a deviation d occurs.

The example of the printed image shown in FIG. 6 shows the tip portion of one bar G1 of the bar code extending in the Y-axis direction printed by the prior art. In the serial head type inkjet printer, higher quality printing can be performed by increasing the number of pass operations for a predetermined area of the print medium 5 to print. The printed image shown in FIG. 6 shows a case where printing is performed by two pass operations.
Here, the −X side is one side in the scanning direction, and the + X side is the other side in the scanning direction.

The bar G1 is configured by arranging five rows of dots arranged in the Y-axis direction in the X-axis direction.
FIG. 6 shows the main dot Dm formed by the main droplet and the satellite dot Ds formed by one separated satellite droplet.
One end of the bar G1, that is, the odd-numbered dot sequence from the end on the −X side, is printed by the pass operation of the first scan in which the head 13 moves in the + X direction, as shown by an arrow in FIG. The even-numbered dot sequence from the end on the X side is printed by the pass operation of the second scan moving in the −X direction.
The satellite droplets land on the main droplets with a deviation d in the direction in which the head 13 moves. Therefore, the satellite droplets of the dot row at the + X side end printed in the first scan moving in the + X direction will land on the outside of the + X direction of the five rows of dot rows constituting the bar G1. As a result, as shown in FIG. 6, the bar width of the bar G1 to be configured with the width W1 becomes a width W2 thicker than the width W1 due to the satellite dots Ds.

On the other hand, in the printing apparatus 1 of the present embodiment, as shown in FIG. 7, the dot row at the + X side end is printed by the second scan moving in the −X direction. That is, when printing the other end of the printed image, the control unit 60 prints in the second scan in which the head 13 is moved from the other to the other. By printing in this way, the satellite droplets in the dot row at the + X side end land in the dot rows of the five rows constituting the bar G1, so that the bar width of the bar G1 is a predetermined width W1. It will be printed.
As a result of printing the dot rows at the + X side end in the second scan moving in the −X direction, the dot rows printed in the second scan become two consecutive rows. It is preferable that the two rows of dots can be printed by the same pass operation, but if the continuous ink ejection from the head 13 is not in time for the moving speed of the carriage 41, the following- Printing is performed by the pass operation of the second scan that moves in the X direction.

Similarly, contrary to the direction of the example shown in FIG. 6, the odd-numbered dot sequence from the −X side end of the bar G1 is printed in the second scan, and the even-numbered dot sequence from the −X side end is printed. , When printed in the first scan, the dot row at the end on the -X side printed in the second scan, which moves in the -X direction, has satellite droplets of the five rows of dots constituting the bar G1. -It will land on the outside in the X direction. In this case, in the printing apparatus 1 of the present embodiment, the dot sequence at the end on the −X side is printed by the first scan that moves in the + X direction. That is, when printing one end of the printed image, the control unit 60 performs printing in the first scan in which the head 13 is moved from one side to the other.

Specifically, such control by the control unit 60 can be performed in the path allocation in the rasterize process described above. In the rasterize process, the image control unit 111 analyzes the printed image, specifically, the image data, and when printing one end of the printed image such as a bar code, a line drawing, or a text, the head 13 Is printed in the first scan that moves the head 13 from one to the other, and when printing the other end of the printed image, the path is assigned so that the print is performed in the second scan that moves the head 13 from the other to the other.

That is, when printing a print image on the printing apparatus 1 including a head 13 for ejecting ink to the print medium 5 and a carriage 41 for reciprocating the head 13 to one side and the other side in the scanning direction with respect to the print medium 5. In the printing method of the present embodiment, when printing one end of a printed image, printing is performed in the first scan in which the head 13 is moved from one side to the other, and the other end of the printed image is printed. When printing the end portion, it is characterized in that printing is performed by a second scan in which the head 13 is moved from the other to the other.

By the way, as can be seen from FIG. 5, the magnitude of the deviation d between the landing positions of the main droplet and the satellite droplet is the main droplet ejected from the head 13, the flight speed of the satellite droplet, and the distance from the head 13 to the print medium 5. , It depends on the moving speed of the head 13.
The flight speed Vm of the main drop, that is, the ejection speed of the main drop can be controlled by the drive signal generated by the drive signal generation circuit 37. The distance from the head 13 to the print medium 5 is determined by the thickness of the print medium 5 and the distance PG between the head 13 and the platen 55 set according to the thickness of the print medium 5. Further, the moving speed of the head 13 can be controlled by the drive signal of the carriage motor generated by the moving control signal generation circuit 35.
In addition, the degree to which the deviation of the landing position of the satellite droplet can be tolerated depends on the specifications of the printed image and the judgment of the user.

Therefore, the printing apparatus 1 is configured to execute the printing method characterized by the present embodiment when necessary. Specifically, the control unit 60 determines the flight distance at which the ink droplets fly from the head 13 to the print medium 5, the flight time at which the ink droplets fly from the head 13 to the print medium 5, the thickness of the print medium 5, and the head 13. When printing one end of the printed image in a predetermined state based on at least one information of the ejection speed of the ink droplet to be ejected, the moving speed of the carriage 41, and the instruction input to the control unit 60, the first Printing is performed in one scan, and when printing the other end of the printed image, printing is performed in the second scan.

Here, the predetermined state is a state in which printing by the printing method characterized by the present embodiment should be performed, that is, in the printing of the prior art, the deviation of the landing position of the satellite droplet should not be allowed. It is in a state of being judged. This predetermined state includes the flight distance in which the ink droplets fly from the head 13 to the print medium 5, the flight time in which the ink droplets fly from the head 13 to the print medium 5, the thickness of the print medium 5, the flight speed of the ink droplets, and the carriage. Since it is a state determined by parameters such as the moving speed of 41, it is sufficiently evaluated and set in advance according to the print quality of a desired printed image such as a bar code in a predetermined standard. Specifically, when the control unit 60 determines that the image control unit 111 is in a preset predetermined state by referring to each parameter in the function of the printer driver when generating print data. , When printing one end of the printed image, printing is performed in the first scan, and when printing the other end of the printed image, printing is performed in the second scan. ..

Even when the image control unit 111 refers to each parameter and determines that the state is a preset predetermined state, printing by the printing method characterized by the present embodiment is performed at the user's discretion. In some cases, it is not necessary to do. On the contrary, even when the image control unit 111 refers to each parameter and determines that the state is not a preset predetermined state, the printing characterized by the present embodiment is characterized by the user's judgment. Sometimes you want to print by method.
The printing apparatus 1 is configured to receive an instruction from the user in preference to the determination of the image control unit 111. Specifically, the image control unit 111 receives the input of the user's instruction from the input unit 112 in the function of the printer driver, and generates print data based on the input instruction.

5 and 6 show an example in which the ejected ink droplet is divided into a main droplet and one satellite droplet as printing by the prior art. Further, FIG. 6 shows an example in which the satellite droplet does not come off to the extent that it exceeds the landing position of the adjacent main droplet. However, depending on the specifications for driving the head 13 and the speed at which the carriage 41 is moved, two or more satellite droplets may be generated, or the satellite droplets may land at a position beyond the landing position of the adjacent main droplet. May be done.
Specifically, as the moving speed of the carriage 41 increases, the number of separated satellite droplets tends to increase, and the degree of the landing position of the separated satellite droplets tends to shift. Further, as the distance from the head 13 to the print medium 5 becomes longer, the number of separated satellite droplets tends to increase, and the degree of the landing position of the separated satellite droplets tends to shift. That is, depending on the moving speed of the carriage 41 and the distance from the head 13 to the print medium 5, satellite droplets are separated from the main droplets ejected to a position inside the position of the main dot Dm forming the end of the printed image. However, it may exceed the position of the main dot Dm forming the end end portion and land on the outside of the printed image.

A specific description will be given with reference to FIG. FIG. 8 shows the landing of the main dot Dm formed by the main droplet and the satellite dots Ds1 and Ds2 formed by the two separated satellite droplets in the printing of the prior art. The satellite dot Ds2 is formed at a position further away from the main dot Dm than the satellite dot Ds1 and at a position where the main drop adjacent to the head 13 in the scanning direction is landed, that is, a position beyond the main dot Dm adjacent to the scanning direction. Not only does it land at a position further away from the outside of the + X direction of the five rows of dots constituting G1, but it also lands outside the −X direction. As a result, the bar width of the bar G1 to be configured with the width W1 becomes a wider width W3 than the width W2 shown in FIG.

In response to such printing, as shown in FIG. 9, in the printing apparatus 1, as shown in FIG. 9, the second dot string from the −X side edge to be printed in the second scan moving in the −X direction is moved in the + X direction. Print in one scan. Further, the dot string at the end on the + X side to be printed in the first scan moving in the + X direction is printed in the second scan moving in the −X direction. That is, in the prior art, the scanning for ejecting the main droplet in which the satellite droplets that land on the outside of the printed image formed by the main dot Dm are generated is the scanning in the direction in which the satellite droplets land on the inside of the printed image. I am trying to be.

Generates satellite droplets that land on the outside of the printed image formed by the main dot Dm The range of positions of the main dot Dm formed by the main droplet, that is, the printed image formed by the main dot Dm in the prior art. The range of the target printed image is such that the scan for ejecting the main droplets that generate satellite droplets that land on the outside is the scan in the direction in which the satellite droplets land on the inside of the printed image. It depends on the magnitude of the deviation d of the landing position of the drop. As described above, the magnitude of the deviation d between the landing positions of the main droplet and the satellite droplet is the main droplet ejected from the head 13, the flight speed of the satellite droplet, the distance from the head 13 to the print medium 5, and the moving speed of the head 13. It depends on such things.

Therefore, in the printing apparatus 1, the range of the main dot Dm of the target at one end of the printed image to be printed in the first scan and the target at the other end of the printed image to be printed in the second scan. The range of the main dot Dm is the flight distance in which the ink droplets fly from the head 13 to the print medium 5, the flight time in which the ink droplets fly from the head 13 to the print medium 5, the thickness of the print medium 5, and the flight speed of the ink droplets. , The moving speed of the carriage 41, is set based on at least one piece of information.
Here, the range of the target main dot Dm at one end of the printed image to be printed in the first scan is, that is, the minimum in the scanning direction of one end of the printed image to be printed in the first scan. The length. Further, the range of the target main dot Dm at the other end of the printed image to be printed in the second scan is, that is, the minimum length in the scanning direction of the other end of the printed image to be printed in the second scan. That's right.

More specifically, the printing apparatus 1 has a length in the scanning direction of one end of the printed image to be printed in the first scan, and a scanning direction of the other end of the printed image to be printed in the second scan. The longer the moving speed of the set carriage 41, the longer the length in.
Further, in the printing apparatus 1, the length of one end of the printed image to be printed in the first scan in the scanning direction and the length of the other end of the printed image to be printed in the second scan in the scanning direction are set. The longer at least one of the set distance from the head 13 to the print medium 5 and the distance from the set head 13 to the platen 55 supporting the print medium 5, the longer the distance.

The minimum lengths of both ends in the scanning direction of the printed image to be printed in the first scan and the second scan correspond to the print quality of a desired printed image such as a bar code in a predetermined standard. And set it after sufficient evaluation in advance. Specifically, the control unit 60 sets in advance when printing one end of the print image by referring to each parameter in the function of the printer driver when the image control unit 111 generates print data. Printing data in which printing is performed in the first scan at a predetermined length, and when printing the other end of the printed image, control is executed in which printing is performed in the second scan at a preset predetermined length. To generate.

As described above, the degree to which the displacement of the landing position of the satellite droplet can be tolerated depends on the specifications of the printed image and the judgment of the user. Therefore, the minimum length in the scanning direction of one end of the printed image to be printed in the first scan and the minimum length in the scanning direction of the other end of the printed image to be printed in the second scan are , May be configured to be set based on the information of the instruction input to the control unit 60.

According to the printing apparatus and printing method of the present embodiment, the following effects can be obtained.
The ink ejected by the head 13 may be split into a main droplet and one or more satellite droplets following the main droplet at the time of ejection or immediately after ejection. Since the landing of the satellite drop is delayed with respect to the landing of the main drop, the landing position in the scanning direction shifts. On the other hand, in the printing apparatus 1 of the present embodiment, when printing one end of a printed image, printing is performed by the first scan in which the head 13 is moved from one to the other, and the other end of the printed image is printed. When printing, printing is performed by a second scan in which the head 13 is moved from the other to the other. By doing so, the satellite droplets will land inward from the end of the desired printed image, and the influence of the satellite droplets will increase the distance from one end of the printed image to the other end. It is possible to prevent the printed image from being distorted due to a long change or a change in the direction in which the distance changes for a long time. That is, for example, it is possible to prevent the bar of the barcode from becoming thick and the shape of the bar from being distorted.

Further, the head 13 varies depending on parameters such as the ejection speed of the ink ejected by the head 13 and the moving speed of the carriage 41, the distance from the head 13 to the platen 55 supporting the print medium 5, and the thickness of the print medium 5. The degree of deviation of the landing position when the ejected ink is separated varies depending on the difference in parameters such as the distance from the head 13 to the print medium 5, the flight distance of the ink flying from the head 13 to the print medium 5, and the flight time. Further, the degree of print quality required for a printed image varies depending on its purpose and application.
According to the present embodiment, the control unit 60 has a flight distance in which the ink flies from the head 13 to the print medium 5, a flight time in which the ink flies from the head 13 to the print medium 5, the thickness of the print medium 5, and the head 13. When printing one end of a printed image in a predetermined state based on at least one information of the ejection speed of the ink to be ejected, the moving speed of the carriage 41, and the instruction input to the control unit 60, the head 13 Is printed in the first scan that moves the head 13 from one to the other, and when printing the other end of the printed image, printing is performed in the second scan that moves the head 13 from the other to the other. Therefore, by appropriately setting a predetermined state based on the above parameters related to the degree of deviation of the landing position when the ejected ink is separated, printing that can obtain desired print quality more effectively and more efficiently. It can be performed.

Further, according to the present embodiment, the minimum length in the scanning direction of one end of the printed image to be printed in the first scan in which the head 13 is moved from one to the other, and the head 13 is moved from the other to the other. The minimum length in the scanning direction of the other end of the printed image to be printed in the second scan to be moved is the flight distance in which the ink flies from the head 13 to the print medium 5, and the ink from the head 13 to the print medium 5. It is set based on at least one piece of information: the flying time, the thickness of the print medium 5, the flying speed of the ink, the moving speed of the carriage 41, and the instruction input to the control unit 60. That is, since the range for suppressing the influence of the landing position deviation is set according to the degree of the landing position deviation when the ejected ink is separated and the desired print quality, it is desired more effectively and efficiently. It is possible to perform printing that can obtain the print quality of.

Further, the faster the moving speed of the carriage 41, the greater the degree of deviation of the landing position when the ejected ink is separated. That is, depending on the moving speed of the carriage 41, the satellite droplets separated from the main droplets ejected inward from the end portion of the printed image cross the end portion of the printed image and land on the outside of the desired printed image. It may end up.
According to the present embodiment, the length of one end of the printed image to be printed in the first scan in which the head 13 is moved from one to the other in the scanning direction, and the second scan in which the head 13 is moved from the other to the other. The length of the other end of the printed image to be printed in the scanning direction is longer as the moving speed of the set carriage 41 is faster. That is, the length in the scanning direction of the end portion to be printed so as to land inside the end portion of the printed image becomes longer as the moving speed of the set carriage 41 increases, so that the satellite droplet becomes the end of the desired printed image. It is suppressed that it lands on the outside of the part.

Further, as the distance from the head 13 to the print medium 5 becomes longer, the degree of deviation of the landing position when the ejected ink is separated tends to increase. That is, depending on the distance from the head 13 to the print medium 5, satellite droplets separated from the main droplets ejected inside the end of the printed image may exceed the end of the printed image to obtain a desired printed image. It may land on the outside.
According to the present embodiment, the length in the scanning direction of one end of the printed image to be printed in the first scan in which the head 13 is moved from one to the other, and the second scan in which the head 13 is moved from the other to the other. The length of the other end of the printed image to be printed in the scanning direction is the distance from the set head 13 to the print medium 5 and the distance from the set head 13 to the platen 55 supporting the print medium 5. The longer at least one of them, the longer it is. That is, the length in the scanning direction of the end portion to be printed so as to land inside the end portion of the printed image is the distance from the set head 13 to the print medium 5, and the set head 13 to the print medium 5. The longer at least one of the distances to the supporting platen 55 is, the longer the satellite droplets are prevented from landing outside the edges of the desired printed image.

In the above-described embodiment, the image control unit 111 prints in the first scan when printing one end of the printed image in generating print data, and prints the other end of the printed image. At that time, it was explained that the path allocation is performed in the raster rise process and the print data is generated so that the control for printing is executed in the second scan. On the other hand, for example, in the prior art, when the printed image G2 as shown in FIG. 10 is printed, the image control unit 111 scans the printed image G2 by one dot as shown in FIG. The print data may be generated so as to be displaced in the direction.
Here, the printed image G2 as shown in FIG. 10 is configured by alternately arranging dot rows whose scanning directions change alternately, and satellite dots Ds of the dot rows at both ends are formed so as to be displaced to the outside of the printed image G2. This is a printed image. By shifting the printed image G2 by one dot in the scanning direction, as shown in FIG. 11, satellite droplets that land on the outside of the printed image G2 will land on the inside of the printed image G2.

1 ... printing device, 5 ... printing medium, 10 ... ink applying unit, 11 ... head unit, 12 ... ink supply unit, 13 ... head, 14 ... head control unit, 15 ... nozzle, 16 ... nozzle row, 20 ... moving unit , 30 ... print control unit, 31 ... in-device interface, 32 ... CPU, 33 ... memory, 34 ... drive control unit, 35 ... movement control signal generation circuit, 36 ... discharge control signal generation circuit, 37 ... drive signal generation circuit, 40 ... scanning unit, 41 ... carriage, 42 ... guide shaft, 50 ... transport unit, 51 ... supply unit, 52 ... storage unit, 53 ... transport roller, 55 ... platen, 60 ... control unit, 100 ... printing unit, 110 ... Image processing unit, 111 ... image control unit, 112 ... input unit, 113 ... display unit, 114 ... storage unit, 115 ... CPU, 116 ... ASIC, 117 ... DSP, 118 ... memory, 119 ... in-device interface, 120 ... general purpose Interface.

Claims (6)

A head that ejects liquid to the print medium,
A carriage that reciprocates the head from one side to the other in the scanning direction with respect to the print medium.
A control unit that controls the drive of the head and the carriage to print a printed image by the liquid is provided.
The control unit
When printing the one end of the printed image, printing is performed in the first scan in which the head is moved from the one to the other.
A printing apparatus that performs printing in a second scan in which the head is moved from the other side to the other side when printing the other end portion of the printed image. The control unit has a flight distance at which the liquid flies from the head to the print medium, a flight time at which the liquid flies from the head to the print medium, a thickness of the print medium, and a liquid ejected by the head. In the case of a predetermined state based on at least one information of the discharge speed, the movement speed of the carriage, and the instruction input to the control unit.
When printing the one end of the printed image, printing is performed in the first scan.
The printing apparatus according to claim 1, wherein when printing the other end portion of the printed image, printing is performed in the second scan. The minimum length of the one end of the printed image to be printed in the first scan in the scanning direction, and the scanning direction of the other end of the printed image to be printed in the second scan. The minimum length in the above is the flight distance of the liquid from the head to the print medium, the flight time of the liquid from the head to the print medium, the thickness of the print medium, and the flight speed of the liquid. The printing apparatus according to claim 1 or 2, which is set based on at least one piece of information of the moving speed of the carriage and the instruction input to the control unit. The length of the one end of the printed image to be printed in the first scan in the scanning direction, and the length of the other end of the printed image to be printed in the second scan in the scanning direction. Is the printing apparatus according to claim 1, wherein the faster the set moving speed of the carriage is, the longer it is. The length of the one end of the printed image to be printed in the first scan in the scanning direction, and the length of the other end of the printed image to be printed in the second scan in the scanning direction. The printing apparatus according to claim 1, wherein at least one of the set distance from the head to the print medium and the set distance from the head to the platen supporting the print medium is longer. A printing method for printing a printed image in a printing apparatus including a head for discharging a liquid to a printing medium and a carriage for reciprocating the head to one side and the other side in the scanning direction with respect to the printing medium. ,
When printing the one end of the printed image, printing is performed in the first scan in which the head is moved from the one to the other.
A printing method in which when printing the other end portion of the printed image, printing is performed by a second scan in which the head is moved from the other side to the one side.

Images